Function fetchRemoteExperimentDetails

pkg/cli/experiments_command.go:580–605

fetchRemoteExperimentDetails reads the state.json from a remote experiment branch.

(repoOverride, branchName, workflowID string)

// fetchRemoteExperimentDetails reads the state.json from a remote experiment branch.
func fetchRemoteExperimentDetails(repoOverride, branchName, workflowID string) (*ExperimentDetails, error) {
	experimentsLog.Printf("Fetching remote experiment details: repo=%s, branch=%s", repoOverride, branchName)

	// Verify the branch exists.
	encodedBranch := url.PathEscape(branchName)
	checkArgs := []string{"api",
		"repos/{owner}/{repo}/branches/" + encodedBranch,
		"--jq", ".name",
		"--repo", repoOverride,
	}
	checkCmd := workflow.ExecGH(checkArgs...)
	if _, err := checkCmd.Output(); err != nil {
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) {
			stderr := strings.TrimSpace(string(exitErr.Stderr))
			if strings.Contains(stderr, "404") || strings.Contains(stderr, "not found") {
				return nil, fmt.Errorf("experiment %q not found in %s", workflowID, repoOverride)
			}
			return nil, fmt.Errorf("failed to fetch experiment branch (exit %d): %s", exitErr.ExitCode(), stderr)
		}
		return nil, fmt.Errorf("failed to fetch experiment branch: %w", err)
	}

	state := readRemoteExperimentState(repoOverride, branchName)
	return experimentDetailsFromState(workflowID, branchName, state), nil
}

// readLocalExperimentState reads state.json from a local git ref (e.g. "origin/experiments/foo").
// Returns an empty state when the file is absent or cannot be parsed.